1. Field of the Invention
This invention relates generally to conveyor systems, and more particularly, to an accumulating conveyor system that expels batch loaded product items in one or more single file outlet channels and accumulates the excess product items in response to the quantity of such product items being transported on plural exit conveyors.
2. Description of the Related Art
There are plural problems in the present state of the art in the field of conveyor systems that are used to deliver product items to downstream equipment, particularly in environments where the product items are delivered at varying rates, or in batches, to the conveyor system. It is, in those situations, not only desired that the conveyor system accumulate the excess product items pending their discharge, but also that the discharge of product items be in a continuous flow of back-to-back product items in single file. It is desired that accumulation of product items in the conveyor system be increased in the event of interruption in the downstream equipment or in the event that the inflow exceeds the desired discharge rate. All this, while maintaining proper orientation of non-round product items during discharge and without undue bumping between the product items, as they may be formed of glass or otherwise be fragile. In addition to minimizing product bumping, which is related to product back pressure, it is important that the product items not be subjected to undue rotation, as such may cause viscous liquid therein to be spun at a different rate that the container itself, resulting in a “gel wobble” instability and consequential toppling of the product items.
The various approaches to the noted problems in the prior art have proven unsatisfactory. Generally speaking, an effort to solve one problem exacerbates another, or creates a new problem. More specifically, in one known arrangement conveyor belts traveling at the same speed transport product items operate in conjunction with a guide that allows the product items to be moved from upstream to downstream locations during operation, and directs the product items to the accumulator section. In addition to requiring a large recirculating area by virtue of its continuous conveyor belt approach to achieving product item accumulation, the known arrangement does not redirect non-circular product items to a desired orientation in the exit port of the conveyor system. Thus, product items having elongated cross-section may temporarily block the exit port, resulting in a single file exit having gaps. In addition, the known arrangement is noisy in its operation as product items are directed to the accumulation area by bumping into product items that are to be discharged and thereby are deflected to the accumulation area. Accumulation capacity is almost exclusively a function of accumulation conveyor belt width in known systems. Thus, increases in accumulation capacity are effected by increasing conveyor belt width, which is achieved at the expense of mechanical complexity in causing belts of increasing width to be curved to form a substantially closed accumulation loop.
Some of these problems have been addressed by other known system. In one such system, a mass of product items is combined into a single file lane by using a moving guide belt disposed over a plurality of parallel conveying surfaces that travel at progressively increasing speeds. The object of the known arrangement, which requires multiple levels of conveyor belts, is to minimize rotation of the product items being conveyed. The product items, which traditionally are guided by stationary guide rails across belts having increasing relative speeds, are known to be rotatable at a speed of rotation that is a function of the rate of linear transport. Product rotation is reduced by forming a guide that is itself in the form of a guide belt, as a substitute for the stationary guide rails. The guide belt is caused to communicate with the product items at an angle and a speed with respect thereto that the rotation is minimized. Significant mechanical complexity and expense are associated with this known approach.
It is, therefore, an object of this invention to provide an accumulating conveyor arrangement that orients product items to conform to a desired exit orientation.
It is another object of this invention to provide an accumulating conveyor arrangement that reduces product bumping.
It is also an object of this invention to provide an accumulating conveyor arrangement that reduces product instability and toppling.
It is a further object of this invention to provide an accumulating conveyor arrangement that provides minimal product back pressure during either accumulation or straight-through discharge of the product items.
It is additionally an object of this invention to provide an accumulating conveyor arrangement that does not rely on curved closed loop conveyor belting to achieve product accumulation.
It is yet a further object of this invention to provide a conveyor system that does not rely on product back pressure to effect single file product discharge.